PORE SWELLING IN BEADS MADE OF CELLULOSE FIBERS AND FIBER FRAGMENTS

The swelling of a new pharmaceutical excipient consisting of highly porous cellulose beads has been studied. Different degrees of swelling were produced by absorption of water and cyclohexane, two liquids with different 'swelling capacity'. The pore size in cellulose beads with different porosities was investigated using the spin echo NMR technique and found to increase due to swelling. The crystallinity of dry and wet cellulose fibres was investigated using C-13 CP/MAS NMR. A basic application of the beads is to use them as well-defined drug carrier particles. The beads can be loaded with drugs by a sorption process from water or organic solvents. It was concluded that it is beneficial to load the beads using drug solutions containing a cellulose swelling liquid.